Recent studies of EPA regulations provide guidelines for reformulated gasolines which will provide a reduction in toxic compounds, eg. benzene, butadiene, formaldehyde, and acetaldehyde in the tailpipe exhaust gases from automobiles. The attainment of lower toxic emissions is not without penalty. Generally, the target octane number must be lowered and refinery capacity must be adjusted to obtain these lower toxic emissions. These solutions are not completely acceptable due to the higher octane requirement of today's automobile engines and the need to conserve crude oil resources. In addition to a reduction in toxic compounds in the tailpipe exhaust products, recent studies indicate that ozone formation in the atmosphere is a function of the reactivity of individual species of organic compounds present in exhaust emissions from spark-ignition internal combustion engines, as well as the quantity of nitrogen oxides (NO.sub.x) emitted from the engines. In particular, a factor deemed of prime importance in the formation of ground level ozone is the maximum reactivity of hydrocarbons and other organic species emitted as exhaust products by gasoline engines. Maximum reactivity is a function of the quantity of given species of emitted exhaust products and the maximum reactivity values or constants for such species. Thus the higher the maximum reactivity (which is directly proportional to species quantity multiplied by the maximum reactivity value for such species), the greater the danger of ground level ozone formation. It is thus of paramount importance to reduce the maximum reactivity of the exhaust products emitted by spark-ignition internal combustion engines, such as passenger cars, buses, trucks, vans, motorcycles, and the like, as well as reducing the total NO.sub.x emissions from such sources. By so doing, it is generally accepted by the scientific community that the extent of smog formation and other dire consequences of atmospheric pollution will be substantially reduced. The atmospheric contaminants needed to produce ozone smog are (1) reactive volatile organic compounds, (2) nitrogen oxides, and (3) sunlight. Note for example, Lowi, Jr. and Carter, "A Method for Evaluating the Atmospheric Ozone Impact of Actual Vehicle Emissions", SAE Paper No. 900710, presented at the 1990 SAE International Congress & Exposition, Detroit, Mich., Feb. 26-Mar. 2, 1990.
Complicating the foregoing problem is the need to provide gasoline fuel compositions which satisfy the demands imposed upon the fuels by the engines in which they are employed. The fuels must have the octane quality, volatility, stability, distillation characteristics, and the like, required for effective use as motor fuels. Of these, achievement of the requisite octane value is perhaps of greatest importance from both the performance and environmental standpoints. In addition, these key gasoline properties must be provided on an economical basis and without excessively or prematurely depleting natural resources such as the world's supply of petroleum. Moreover, these key gasoline properties must be provided within the capabilities and production capacities of the petroleum refining industry.
This invention is believed to provide a highly efficacious way of reducing the amount of toxic compounds and maximum reactivity of exhaust products emitted by spark-ignition internal combustion engines, as well as reducing the total NO.sub.x emissions. In addition, this invention is deemed to provide a most effective and efficient way of providing and using gasolines of suitable octane values while concomitantly reducing the potential for ground ozone formation, smog formation, and other grievous consequences of atmospheric pollution. Accordingly, this invention is believed to provide an increase in refinery capacity and a decrease in refinery emissions by providing an efficacious means for formulating gasoline with a target octane number.